Question

Name two important products of destructive distillation of coal. Name the residue left in this process. Give one main use of this residue.

Answer 1

Step 1: Destructive Distillation

The chemical process takes place on unprocessed materials. When organic substances are decomposed by heat in the absence of air is known as destructive distillation. Products obtained from the destructive distillation of coal are coal gas and coal tar.

1. Coal is one of the most commonly used natural hydrocarbon substances. It is obtained by mining.
2. Coal is a black or brownish-black rock-like substance made up of carbon, hydrogen, nitrogen, or sulfur.
3. Coal formation takes millions of years. It is formed by the decomposition of organic plants, which undergoes heat and pressure in the absence of oxygen for about 300 million years.
4. When coal is heated in the air, coal burns down and produces mainly (carbon dioxide)CO₂. It is used to generate electricity for power stations.

Step 2: Write the chemical equation for destructive distillation.

$\mathrm{Coal}\stackrel{\mathrm{Destructive}\mathrm{distillation}}{\to }\mathrm{Coke}+\mathrm{Coal}\mathrm{tar}+\mathrm{Coal}\mathrm{gas}$

1. Coal gas is a mixture of hydrogen, methane, carbon monoxide, and other gases used for domestic fuel. In contrast, coal tar is a thick black liquid that has n unpleasant smell. It is a complex compound and separated by different processes for further use.
   
2. When coal undergoes destructive distillation, coke is obtained as residue. Coke is a porous and black substance. It is a pure form of carbon with 90% carbon content.
   
3. It is mainly used to manufacture steel and other materials and is also used as a reducing agent in extracting metals. Example- iron, Zinc e.t.c.

Step 3: Conclusion

The two products of the destructive distillation are coal and coal tar. The residue left in the process is coke used in manufacturing steel.